Abstract
Understanding the molecular phylogenetic tree is considered necessary for the biology curriculum of upper secondary school in many countries. Previous research revealed that Japanese high school students did not adequately understand the meanings of each computational operation in the activity of depicting the molecular phylogenetic tree (Yamanoi et al., 2012b). One possible reason for this is an inadequate understanding of the mechanism by which molecular variations among species arise. So, this research tries to help Japanese high school students understand the principles of the molecular phylogenetic tree by using an existing activity (Westerling, 2008) with some modifications. Classes using the modified teaching material for high school students were conducted. On the basis of pre- and posttest results and the descriptions by the students after classes, this material was considered useful in promoting the students’ understanding of the principle of the molecular phylogenetic tree based on the neutral theory. Also, introducing this teaching material before the activity of depicting the molecular phylogenetic tree could help learners overcome most cognitive difficulties accompanying the computational operations.
